A controversial new study contends nearly 655,000 Iraqis have died because of the war, suggesting a far higher death toll than other estimates.
The timing of the survey's release, just a few weeks before the U.S. congressional elections, led one expert to call it "politics."

In the new study, researchers attempt to calculate how many more Iraqis have died since March 2003 than one would expect without the war. Their conclusion, based on interviews of households and not a body count, is that about 600,000 died from violence, mostly gunfire. They also found a small increase in deaths from other causes like heart disease and cancer.

"Deaths are occurring in Iraq now at a rate more than three times that from before the invasion of March 2003," Dr. Gilbert Burnham, lead author of the study, said in a statement.

The study by Burnham, of the Johns Hopkins Bloomberg School of Public Health, and others is to be published Thursday on the Web site of The Lancet, a medical journal.

An accurate count of Iraqi deaths has been difficult to obtain, but one respected group puts its rough estimate at closer to 50,000. And at least one expert was skeptical of the new findings.

"They're almost certainly way too high," said Anthony Cordesman of the Center for Strategic & International Studies in Washington. He criticized the way the estimate was derived and noted that the results were released shortly before the Nov. 7 election.

"This is not analysis, this is politics," Cordesman said.

The work updates an earlier Johns Hopkins study _ that one was released just before the November 2005 presidential election. At the time, the lead researcher, Les Roberts of Hopkins, said the timing was deliberate. Many of the same researchers were involved in the latest estimate.

Speaking of the new study, Burnham said the estimate was much higher than others because it was derived from a house-to-house survey rather than approaches that depend on body counts or media reports.

A private group called Iraqi Body Count, for example, says it has recorded about 44,000 to 49,000 civilian Iraqi deaths. But it notes that those totals are based on media reports, which it says probably overlook "many if not most civilian casualties."

For Burnham's study, researchers gathered data from a sample of 1,849 Iraqi households with a total of 12,801 residents from late May to early July. That sample was used to extrapolate the total figure. The estimate deals with deaths up to July.

The survey participants attributed about 31 percent of violent deaths to coalition forces.

Accurate death tolls have been difficult to obtain ever since the Iraq conflict began in March 2003. When top Iraqi political officials cite death numbers, they often refuse to say where the numbers came from.

The Health Ministry, which tallies civilian deaths, relies on reports from government hospitals and morgues. The Interior Ministry compiles its figures from police stations, while the Defense Ministry reports deaths only among army soldiers and insurgents killed in combat.

The United Nations keeps its own count, based largely on reports from the Baghdad morgue and the Health Ministry.

The major funder of the new study was the Massachusetts Institute of Technology.